net: Fix a memmove bug in dev_gro_receive()

commit e5093aec2e6b60c3df2420057ffab9ed4a6d2792 upstream.

>Xin Xiaohui wrote:
> I looked into the code dev_gro_receive(), found the code here:
> if the frags[0] is pulled to 0, then the page will be released,
> and memmove() frags left.
> Is that right? I'm not sure if memmove do right or not, but
> frags[0].size is never set after memove at least. what I think
> a simple way is not to do anything if we found frags[0].size == 0.
> The patch is as followed.
...

This version of the patch fixes the bug directly in memmove.

Reported-by: "Xin, Xiaohui" <xiaohui.xin@intel.com>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/net/core/dev.c b/net/core/dev.c
index d1d0ee2f1d8a30488c45e9505956886670a25e4b..0efe23a3a13ed8398411df8facaac2a15664705b 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2664,7 +2664,7 @@ pull:
                        put_page(skb_shinfo(skb)->frags[0].page);
                        memmove(skb_shinfo(skb)->frags,
                                skb_shinfo(skb)->frags + 1,
-                               --skb_shinfo(skb)->nr_frags);
+                               --skb_shinfo(skb)->nr_frags * sizeof(skb_frag_t));
                }
        }